The GOA (Gate Drive On Array) circuit is to manufacture the gate scan drive circuit on the array substrate by utilizing the present liquid crystal display array process for achieving the driving method of scanning row by row. It possesses merits of the production cost decrease and the narrow frame design, and is utilized by many kinds of displays. The GOA circuit possesses two fundamental functions: one is to input the gate drive pulse to drive the gate line in the panel, and to activate the TFT (Thin Film Transistor) in the display area for charging the pixel via the gate line; two is for the shift register, and as the output of the nth gate drive pulse is accomplished, the output of the n+1th gate drive pulse can be performed with clock control and so on.
The GOA circuit comprises a Pull-up circuit, a Pull-up control circuit, a Pull-down circuit, a Pull-down control and a Boost circuit in charge of boosting voltage level. Specifically, the pull-up circuit is mainly in charge of outputting the inputted clock signal (Clock) to the gate of the thin film transistor as being the driving signals of the liquid crystal display. The pull-up control circuit is in charge of activating the pull-up circuit, and is generally functioned by the signal transferred from the GOA circuit of the former stage. The Pull-down circuit is in charge of rapidly pulling down the scan signal to low voltage level after outputting the scan signal. That is, the voltage level of the gate of the thin film transistor is pulled down to be low voltage level; the Pull-down holding circuit is in charge of keeping the scan signal and the signal of the Pull-up circuit (Q point in general) in off state (i.e. the set negative voltage level), and generally, two Pull-down holding circuits function, alternately. The boost circuit is in charge of a second boost to the voltage level of the Q point for ensuring the G(N) normal output of the pull-up circuit.
Different GOA circuits can utilize different processes. The Low Temperature Poly-Silicon (LTPS) process possesses advantages of higher electron mobility and mutual technology, which is widely utilized in the small and medium displays. The CMOS (Complementary Metal Oxide Semiconductor) LTPS process possesses advantages of low power consumption, higher electron mobility and wide noise margin, and thus is gradually utilized by panel makers. Therefore, there is a need to develop the GOA circuit corresponding to the CMOS LTPS process.